Part of the Dudar-Cressy vocabulary, 'sea shanty' is a word that comes between Scrim and Bo Diddley , meaning pretty crappy or not very good, something thats just not up to par. But it could always be worse ( Ie Scrim)
( list of related Dudar-Cressy Vocabulary see Flash , Bo Diddley and Scrim.)
That movie last night , I hated it , it was so sea shanty.
That joke was at the level of sea shanty.
Homework on the weekend is sea shanty.